182 research outputs found

    Magnetoresistivity tensor of arsenic (25.5 at. %) – Antimony alloy single crystals.

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    An experimental investigation of the galvanomagnetic effects in a particular A7 structure material and a theoretical study of the symmetry properties of the transport tensors are presented. For the experimental study, arsenic-antimony alloy single crystals have been grown at the minimum melting point composition (25.5 at. % A8) where the solidus and liquids touch on the phase diagram. Dislocation etch pit studies have been made on the (111) cleavage faces. Measurements have been made between 1.5K and 300K of the twelve components that define the low-field magnetoresistivity tensor and of the orientation dependence of the tensor components P (_11) (B (_1), B (_2), 0), P (_11) (B (_1), 0 B (_3)) and P (_21) (B (_1), 0, B (_3)). A least-mean-squares fit to the data has been used to obtain the model parameters for a two band, multivalley, ellipsoidal Fermi surface. The alloy model parameters are compared and contrasted with those of the parent elements. The alloy is semi metallic. In the theoretical work, the forms of the magnetic field dependent transport tensors are established for all 32 crystallographic point groups. A formulation of galvanomagnetic and thermomagnetic effects based on the separation of the tensor components into “even” and “odd” functions of the applied magnetic field is given. It is shown that the Umkehr effect is a natural result of the anisotropy of crystals

    Trigeminal nerve and pathologies in magnetic resonance imaging : a pictorial review

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    A variety of conditions may affect the trigeminal nerve. Magnetic resonance imaging is the modality of choice when trigeminal nerve pathology is suspected, and this modality plays an essential role in detecting causes. This review illustrates some of the pathological conditions relevant to the trigeminal nerve in magnetic resonance imaging

    A size-dependent functionally graded sinusoidal plate model based on a modified couple stress theory

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    A size-dependent model for bending and free vibration of functionally graded plate is developed based on the modified couple stress theory and sinusoidal shear deformation theory. In the former theory, the small scale effect is taken into consideration, while the effect of shear deformation is accounted for in the latter theory. The equations of motion and boundary conditions are derived from Hamilton’s principle. Analytical solutions for the bending and vibration problems of simply supported plates are obtained. Numerical examples are presented to illustrate the influences of small scale on the responses of functionally graded microplates. The results indicate that the inclusion of small scale effects results in an increase in plate stiffness, and consequently, leads to a reduction of deflection and an increase in frequency. Such small scale effects are significant when the plate thickness is small, but become negligible with increasing plate thickness

    Value of shoulder US compared to MRI in infants with obstetric brachial plexus paralysis

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    PURPOSEChildren with brachial plexus birth injury (BPBI) may eventually develop glenohumeral instability due to development of unbalanced muscular strength. Our major goal in this study is to compare the accuracy of physical examination and ultrasonography (US) in determination of glenohumeral instability in infants with BPBI compared with magnetic resonance imaging (MRI) as a gold standard, and to investigate the role and value of US as a screening modality for assessing glenohumeral instability. METHODSForty-two consecutive patients (mean age, 2.3±0.8 months) with BPBI were enrolled into this prospective study. Patients were followed up with physical examination and US with dynamic evaluation in 4–6 weeks intervals. Patients who developed glenohumeral instability based on physical examination and/or US (n=21) underwent MRI. Glenohumeral instability was defined as alpha angle >30° and percentage of posterior humeral head displacement >50%. Diagnostic accuracy of physical examination and US was calculated and quantitative parameters were compared with Wilcoxon test.RESULTSGlenohumeral instability was confirmed with MRI in 15 of 21 patients. Accuracy and sensitivity of physical examination and US were 47%, 66% and 100%, 100%, respectively in determination of glenohumeral instability. No significant difference was found for the alpha angle (p = 0.173) but the percentage of posterior humeral head displacement was statistically significant between US and MRI (p = 0.028).CONCLUSIONOur results indicate that US with dynamic evaluation is a good alternative for MRI in assessment of glenohumeral instability in infants with BPBI, since it is highly accurate and specific, and quantitative measurements used for glenohumeral instability were comparable to MRI. US can be used as a screening method to assess glenohumeral instability in infants with BPBI

    New European Metrology Network for advanced manufacturing

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    Advanced manufacturing has been identified as one of the key enabling technologies with applications in multiple industries. The growing importance of advanced manufacturing is reflected by an increased number of publications on this topic in recent years. Advanced manufacturing requires new and enhanced metrology methods to assure the quality of manufacturing processes and the resulting products. However, a high-level coordination of the metrology community is currently absent in this field and consequently this limits the impact of metrology developments on advanced manufacturing. In this article we introduce the new European Metrology Network (EMN) for Advanced Manufacturing within EURAMET, the European Association of National Metrology Institutes (NMIs). The EMN is intended to be operated sustainably by NMIs and Designated Institutes in close cooperation with stakeholders interested in advanced manufacturing. The objectives of the EMN are to set up a permanent stakeholder dialogue, to develop a Strategic Research Agenda for the metrology input required for advanced manufacturing technologies, to create and maintain a knowledge sharing programme and to implement a web-based service desk for stakeholders. The EMN development is supported by a Joint Network Project within the European Metrology Programme for Innovation and Research

    Increased ocular wall thickness and decreased globe volume in children with mucopolysaccharidosis type VI

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    PURPOSElthough clinical ophthalmologic findings have been reported, no study documented magnetic resonance imaging (MRI) findings in mucopolysaccharidosis (MPS) type VI. The aim of this study was to determine the ophthalmologic imaging findings of MPS type VI in the pediatric age group retrospectively.METHODSBrain MRIs of 10 patients with MPS type VI and 49 healthy children were evaluated independently by two pediatric radiologists for the following characteristics: globe volume, ocular wall thickness, and optic nerve sheath diameter for each orbit. The means of the measurement of each group were compared by using an independent t-test. Agreement and bias between reviewers were assessed by intra-class correlation coefficients (ICC).RESULTSA total of 59 children [32 girls (54.23%), 27 boys (45.77%); age range, 4-16 years; mean age, 10.37 ± 3.73 years] were included in the study. Statistical analysis revealed smaller eyeballs and thicker ocular walls of patients with MPS type VI (P < .001 and P < .001, respectively). However, there was no statistically significant difference in terms of optic nerve sheath diameter between the two groups (P=.648).CONCLUSIONPatients with MPS type VI displayed reduced globe volumes and increased ocular wall thicknesses compared to the healthy children. Therefore, we recommend that ophthalmologic imaging findings might prove to be an auxiliary tool in the diagnosis of MPS patients

    G Protein Subunit Dissociation and Translocation Regulate Cellular Response to Receptor Stimulation

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    We examined the role of G proteins in modulating the response of living cells to receptor activation. The response of an effector, phospholipase C-β to M3 muscarinic receptor activation was measured using sensors that detect the generation of inositol triphosphate or diacylglycerol. The recently discovered translocation of Gβγ from plasma membrane to endomembranes on receptor activation attenuated this response. A FRET based G protein sensor suggested that in contrast to translocating Gβγ, non-translocating Gβγ subunits do not dissociate from the αq subunit on receptor activation leading to prolonged retention of the heterotrimer state and an accentuated response. M3 receptors with tethered αq induced differential responses to receptor activation in cells with or without an endogenous translocation capable γ subunit. G protein heterotrimer dissociation and βγ translocation are thus unanticipated modulators of the intensity of a cell's response to an extracellular signal

    Measurement of gauge blocks by interferometry

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    The key comparison EURAMET.L-K1.2011 on gauge blocks was carried out in the framework of a EURAMET project starting in 2012 and ending in 2015. It involved the participation of 24 National Metrology Institutes from Europe and Egypt, respectively. 38 gauge blocks of steel and ceramic with nominal central lengths between 0.5 mm and 500 mm were circulated. The comparison was conducted in two loops with two sets of artifacts. A statistical technique for linking the reference values was applied. As a consequence the reference value of one loop is influenced by the measurements of the other loop although they did not even see the artifacts of the others. This influence comes solely from three "linking laboratories" which measure both sets of artifacts. In total there were 44 results were not fully consistent with the reference values. This represents 10% of the full set of 420 results which is a considerable high number. At least 12 of them are clearly outliers where the participants have been informed by the pilot as soon as possible. The comparison results help to support the calibration and measurement capabilities (CMCs) of the laboratories involved in the CIPM MRA

    EpiCRISPR targeted methylation of Arx gene initiates transient switch of mouse pancreatic alpha to insulin-producing cells

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    Introduction: Beta cell dysfunction by loss of beta cell identity, dedifferentiation, and the presence of polyhormonal cells are main characteristics of diabetes. The straightforward strategy for curing diabetes implies reestablishment of pancreatic beta cell function by beta cell replacement therapy. Aristaless-related homeobox (Arx) gene encodes protein which plays an important role in the development of pancreatic alpha cells and is a main target for changing alpha cell identity. Results: In this study we used CRISPR/dCas9-based epigenetic tools for targeted hypermethylation of Arx gene promoter and its subsequent suppression in mouse pancreatic αTC1-6 cell line. Bisulfite sequencing and methylation profiling revealed that the dCas9-Dnmt3a3L-KRAB single chain fusion constructs (EpiCRISPR) was the most efficient. Epigenetic silencing of Arx expression was accompanied by an increase in transcription of the insulin gene (Ins2) mRNA on 5th and 7th post-transfection day, quantified by both RT-qPCR and RNA-seq. Insulin production and secretion was determined by immunocytochemistry and ELISA assay, respectively. Eventually, we were able to induce switch of approximately 1% of transiently transfected cells which were able to produce 35% more insulin than Mock transfected alpha cells. Conclusion: In conclusion, we successfully triggered a direct, transient switch of pancreatic alpha to insulin-producing cells opening a future research on promising therapeutic avenue for diabetes management. 1 Introductio

    A membrane-associated movement protein of Pelargonium flower break virus shows RNA-binding activity and contains a biologically relevant leucine zipper-like motif

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    [EN] Two small viral proteins (DGBp1 and DGBp2) have been proposed to act in a concerted manner to aid intra- and intercellular trafficking of carmoviruses though the distribution of functions and mode of action of each protein partner are not yet clear. Here we have confirmed the requirement of the DGBps of Pelargonium flower break virus (PFBV), p7 and p12, for pathogen movement Studies focused on p12 have shown that it associates to cellular membranes, which is in accordance to its hydrophobic profile and to that reported for several homologs. However, peculiarities that distinguish p12 from other DGBp52 have been found. Firstly, it contains a leucine zipper-like motif which is essential for virus infectivity in plants. Secondly, it has an unusually long and basic N-terminal region that confers RNA binding activity. The results suggest that PFBV p12 may differ mechanistically from related proteins and possible roles of PFBV DGBps are discussed. (C) 2011 Elsevier Inc. All rights reserved.We gratefully thank Dr. Vicente Pallas for critical reading of the manuscript and Dolores Arocas and Isabella Avellaneda for their technical assistance. This research was supported by grant BFU2006-11230 and BFU2009-11699 from the Ministerio Ciencia e Innovacion (MICINN, Spain) and by grants ACOM/2006/210 and ACOMP/2009/040 (Generalitat Valenciana, GV) to C. H. S. M.-T. was the recipient of a predoctoral fellowship from GV and of a predoctoral contract from MICINN.Martínez Turiño, S.; Hernandez Fort, C. (2011). A membrane-associated movement protein of Pelargonium flower break virus shows RNA-binding activity and contains a biologically relevant leucine zipper-like motif. Virology. 413(2):310-319. https://doi.org/10.1016/j.virol.2011.03.001S310319413
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